Super Alloy Monel 404™ (UNS N04404)

Topics Covered

Introduction
Chemical Composition
Physical Properties
Mechanical Properties
Thermal Properties
Fabrication and Heat Treatment
     Machinability
     Forming
     Welding
     Heat Treatment
     Forging
     Hot Working
     Cold Working
     Annealing
     Hardening
Applications

Introduction

Super alloys have the capacity to function in environments with very high temperatures and severe mechanical stress. They have good creep and oxidation resistance, and are available in a variety of shapes. Solid-solution hardening, work hardening, and precipitation hardening are performed for increasing the strength of the super alloys. They are broadly classified into three types such as cobalt-based, nickel-based, and iron-based alloys.

Super Alloy Monel 404™ is a copper-nickel alloy. It has low magnetic permeability and good brazing capacity. The following datasheet gives more details about super alloy Monel 404™.

Chemical Composition

The chemical composition of super alloy Monel 404™ is outlined in the following table.

Elements Content (%)
Nickel, Ni 52-57
Copper, Cu ≤ 45.5
Iron, Fe ≤ 0.50
Sulfur, S 0.024
Carbon, C ≤ 0.15
Silicon, Si ≤ 0.10
Manganese, Mn ≤ 0.10
Aluminum, Al ≤ 0.050

Physical Properties

The following table shows the physical properties of super alloy Monel 404™.

Properties Metric Imperial
Density 8.91 g/cm³ 0.322 lb/in³
Melting point 1315°C 2400°F

Mechanical Properties

The mechanical properties of super alloy Monel 404™ are outlined in the following table.

Properties Metric Imperial
Tensile strength at break (annealed) 483 MPa 70000 psi
Tensile strength at break (stress relieved) 655 MPa 95000 psi
Tensile strength at break (hard) 758 MPa 110000 psi
Yield strength (annealed) 172 MPa 25000 psi
Yield strength (stress relieved) 517 MPa 75000 psi
Yield strength (hard) 689 MPa 100000 psi
Elastic modulus 169 GPa 24500 ksi
Poisson’s ratio 0.295 0.295

Thermal Properties

The thermal properties of super alloy Monel 404™ are given in the following table.

Properties Metric Imperial
Thermal expansion co-efficient (at 21-93°C/69.8-199°F) 13.3 µm/m°C 7.39 µin/in°F

Fabrication and Heat Treatment

Machinability

Super alloy Monel 404™ is machined using conventional machining methods which are used for iron-based alloys. Commercial coolants are used for performing machining operations. High-speed operations such as grinding, milling, or turning, are performed using water-based coolants. Heavy lubricants are used for tapping, drilling, boring or broaching.

Forming

Super alloy Monel 404™ can be formed using all conventional techniques.

Welding

Super alloy Monel 404™ is welded using gas-tungsten arc welding, submerged-arc welding, shielded metal-arc welding, and gas metal-arc welding methods.

Heat Treatment

Except for annealing, super alloy Monel 404™ does not respond to heat treatment

Forging

Super alloy Monel 404™ has good forgeability.

Hot Working

Super alloy Monel 404™ has good hot working capacity.

Cold Working

Super alloy Monel 404™ can be cold worked using standard tooling. Soft die materials are used for producing good finish and reduce galling problems.

Annealing

Super alloy Monel 404™ is annealed at 760°C (1400°F) for 1 hr.

Hardening

Super alloy Monel 404™ can be hardened by cold working.

Applications

Super alloy Monel 404™ is used in ceramic-to-metal sealing and capsules for transistors.

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